1. Field of the Invention
The present invention relates to a cutter unit, particularly to an improvement in the control over the operation of a cutter unit incorporated in a printer.
2. Description of the Prior Art
In prior art a guillotine type or pizza cutter type paper cutter is incorporated in a POS (Point of Sale System) printer, and it is configured to detect a cutter blade in a reference position by a position detector such as a switch or a photosensor and drive it by a drive source such as a DC motor or a stepping motor. Such a cutter blade, a position detector and a drive source are accommodated in a case to constitute a cutter unit. The cutter unit can be incorporated in a printer such as POS printer, cash register, various types of ticketing machine and controlled by the printer.
Japanese Patent Application Publication No. 2001-158140, No. H5-154791 and No. 2002-346987 disclose such a printer which includes the cutter unit, a drive circuit for a motor as a drive source, a motor control circuit, and a detection circuit to process detected results of a position detector to control the cutter unit.
In this printer, the cutter unit is required to perform a simple operation of fully cutting or partially cutting a printed paper only. However, to realize the cutting operation, the printer has to be designed with the following basic cutter operations taken into account:
1. Initial operation to set the cutter blade at the reference position
2. Two types of cutting operation as partial cut or full cut-off
3. Error handling when anomaly occurs
To design these basic operations, the printer needs to be designed precisely in conformity with the specification of the cutter unit, which is very troublesome and time consuming. There may be a case where some content of the specification is overlooked.
This imposes an extraneous burden on the designing of the printer. In addition, the operational quality of the cutter unit is degraded if the precise designing conformity is not realized.